Broadway “Beast” James Barbour laid his furry mitts on yet a second underage aspiring actress – this one only 13 years old – prosecutors now charge.

Barbour, a highly regarded star of musical theater who once played the Beast in “Beauty and the Beast,” was in Manhattan Supreme Court yesterday to answer charges that five years ago he seduced a star-struck 15-year-old actress wannabe in his Broadway dressing room.

No sooner had Barbour delivered his line, “Not guilty,” than prosecutors upstaged him with their bombshell about a previous alleged victim – an even younger girl who had also come to Barbour with her starry-eyed hopes for a career in theater.

The 13-year-old contacted authorities only after reading about the alleged attack on the 15-year-old in The Post, sources said.

The younger girl’s alleged seduction happened in California seven years ago – too long ago to prosecute. But Manhattan Assistant District Attorney Maxine Rosenthal told the judge she’ll seek to have that girl’s uncharged allegations count against Barbour upon his sentencing for the statutory contact with the 15-year-old. The 15-year-old is now a 20-year-old woman with a career in the theater. Prosecutors said she came forward earlier this year – just before the alleged contact would have become unprosecutable under the five-year statute of limitations – out of concern that there were indeed other victims.

The older alleged victim told authorities that was introduced to Barbour – a graduate of her New Jersey high school who is 20 years her senior – through the school’s drama teacher.

She’s accused him of seducing her into a sexual groping session back in June 2001 in his dressing room at the Brooks Atkinson Theatre on West 47th Street after his performance as Rochester in the Tony-award-winning “Jane Eyre.”

Later that night – as her parents, and Barbour’s own girlfriend, sat together at an Eighth Avenue restaurant – Barbour allegedly fondled her under the table. A month later, he invited her back to the city, and they exchanged oral sex at his West 98th Street apartment, she told cops.

In all, the alleged conduct adds up to a nine-count indictment carrying anywhere from zero to four years behind bars.

Barbour is strenuously denying that he ever did anything more than kiss the girl. Yesterday, his face visibly paled when the prosecutor told the judge that she wants the Beast caged.

“It is a strong case,” Rosenthal said, noting that, earlier this year, the older alleged victim caught Barbour on tape making “admissions” and admitting repeatedly that his behavior was “unethical.”

The handsome Barbour came to court wearing a well-tailored gray suit, an open-necked dress shirt, a wedding band on his ring finger and an attractive brunette – who also sported a wedding ring – on his arm. The couple declined to speak to reporters.

Court documents released yesterday show Barbour was apparently far chattier when he was arrested in his native Los Angeles back in April – showing no hesitancy to sling a little mud on his alleged victim.

In his handwritten statements to cops, he denied doing anything more than kissing the 15-year-old as they lay together on his bed and talked dirty.

“She talked about [oral sex],” he said. When the girl suggested “sexual intercourse,” “I sort of freaked out, said she was 16 and that I couldn’t do this.”

Barbour also chewed the precinct scenery with such apparent clinkers as that the girl said she wasn’t a virgin, that she insisted she was 16, and that he was only trying to act as her “mentor.”

Barbour is due back in court Dec. 20.

Prosecutors ask that anyone with related criminal allegations against Barbour call them at (212) 335-9373.